Spray nozzle



D. J. PEEPS SPRAY NOZZLE April 5, 1949.

Filed May 29, 1944 2| BY Donald J Peeps ATTORNEY Patented Apr. 5, 1949 SPRAY NOZZLE Donald J. Peeps, Toledo, Ohio, assignor to The De Vilbiss Company, lloledo, Ohio, a corporation of Ohio Application May 29, 1944, Serial No. 537,918

1 Claim. 1

This invention relates to nozzles for spray coating devices using air for atomizing the coating material and particularly to such nozzles having an atomizing and discharging chamber with a plurality of outlet ports for discharging the atomized material in a plurality of directions.

A nozzle of this general type is the subject of my co-pending application No. 421,140 filed December 1, 1941, Patent Number 2,356,944.

Difficulty has been encountered with the nozzles described in this previous application in regard to supplying sufiicient material to the rearwardly directed discharge ports.

The primary purpose of this invention is to overcome this difliculty.

Another object of the invention is to arrange the discharge ports so as to increase the coating scope in regard to cavities having variously facing surfaces within a limited space.

The design of a nozzle, utilizing air for atomizing and discharging a coating material, is quite technical in view of the two fluids involved and the fact that the proportion of liquid to air is very low-frequently as small as one per cent and averaging little more than that. The feeding pressures, the velocities, weight and proportions of the two fluids all afiect results obtained. Naturally the specifications of such a nozzle may not be determined from results obtained with a hydraulic type of nozzle handling a liquid alone. Such a fluid not having the compressibility of air or of a mixture of air and liquid, is more inclined to react uniformly throughout a circuit to a change in pressure, direction or velocity. While a liquid. alone issuing from a port under pressure spreads only slightly, when particles of coating liquid are dispersed through compressed air they Will be spread considerably with the expanding air as the mixture is discharged.

Other objects of the invention will appear from the following specification and the accompanying drawings in which:

Figure 1 is a longitudinal sectional view of a spray gun extension with a discharge nozzle embodying my invention;

Figure 2 is a front elevation of the nozzle on the extension of Figure 1;

Figure 3 is a side elevational view of the discharge nozzle of Figures 1 and 2;

Figure 4 is a front elevation of another form of nozzle embodying my invention;

Figure 5 is a side elevational view of the nozzle shown in Figure 4;

Figure 6 is a front elevation of a third form of nozzle embodying my invention;

Figure '7 is a side elevational view of the nozzle in Figure 6;

Figure 8 is a somewhat schematic presentation of a spray gun extension with a nozzle of my invention applying coatings to various interior surfaces of a shell.

The spray gun extension shown in Figure 1 has an exterior air tube I to which is fastened an air tip 2. Within the tube l and the tip 2 are liquid tubes 3 and l, to the latter of which is fastened a liquid tip 5.

The end of the liquid close-off needle valve 8 is shown seated within the inner end of the tube 4. Upon the air tip 2 is attached a liquid and air, mixing and discharge nozzle I. Liquid enters this nozzle from the liquid tip 5 and air enters the nozzle from the annular air passage formed between the liquid tip 5 and the air tip 2. Within the nozzle '1, immediately ahead of the tips 2 and 5, is a cylindrical chamber 8. At the forward end this chamber has a tapered or converging section 9. In this converging wall section is an annular series of six equally spaced ports l0 directed forwardly at an angle of approximately 60 to the longitudinal axis of the nozzle. Beyond these ports is a second cylindrical chamber II with a diameter smaller than that of chamber 8. At the forward end of this chamber the wall has a converging section 12. From this section there is another annular series of six ports l3 directed rearwardly at an angle of approximately 60 to the axis of the nozzle. These ports l3 are in staggered relation to the ports Ill whereby the atomized material discharged from them will pass between jets of atomized material coming from ports ill. Beyond the converging wall section I2 is a short cylindrical section it with a diameter less than the diameter of the chamber II. From the section It the walls of the nozzle expand to a diameter greater than that of chamber 8 and then contract to merge and form a rounded end.

From the chamber 15 thus formed six ports l8 are directed forwardly. The arrangement of the ports 56 may be seen more clearly in Figures 2 and 3 which present other views of the atomizing and discharge nozzle shown in Figure 1.

In Figures 2 and 3 the nozzle is turned on its longitudinal axis about from the position in which it is shown in Figure 1.

The nozzle shown in Figures 4. and 5 has, instead of the forwardly directed round discharge ports 5, a slot ll. While having the lateral ports i3 directed rearwardly it does not have the forwardly directed lateral ports H]. In Figures 6 and 7 is a third form of my invention in which the nozzle has three slots discharging from the large end chamber. One of these slots indicated at 18 is centrally positioned like slot H in the nozzle in Figures 4 and 5, while the other two I 9 are placed on opposite sides of the first slot. Instead of having rearwardly directed ports 13 the nozzle shown in these figures has a slot 29 discharging from the center portion of the nozzle and -.dir.ected rearwardly. The interior shape of the nozzles o'f l igures 4, 5, 6, and 7 is the same as that of the nozzle of Figure 1 except for the omission of the short initial cylindrical passage 8 and the converging section 9.

The nozzle shown on the extension :in FigureB is the same as that of Figures 1,2 and '3. When such a nozzle is used for coating interior surfaces of a cavity, such as the interiorof a shell 21 as indicated, either the shell or thenozzle is revolved while relative movement along their 1 common longitudinal axis bringsithe nozzle within the shell. .As indicated =m-aterial discharged from 'the ports l6 coat the interior end 22 of the cavity while spray material issuingfrom the forwardly inclined ports t9 .coatsurfaces-zs which-faeerearwardly of the nozzle and :material discharged by rearwardlydirected ports I3 coat surfaces 24 facingforwardly of the nozzle.

.As the shell 2| or the nozzle rotatesinrelation .to the other and relative movement occursbe- .tween the shell and the nozzle .along their common longitudinal axis, spray patterns directed .Iaterally .from ports H] .and 1:3 sweep ,around'the 'interiorsurfaces of the shell overlapping on each turnand progressively coat the surfaces toward which they are directed. Simultaneously the further interior end of the shell is-coated by ma- .terial issuing from the forward ports 16 of .the

nozzle.

.In previously designed nozzles having ports positioned to discharge in varying directions,

these ports directed more in line with the for- Ward movement of the atomizing material through the nozzle have received proportionatelymore of .the .material than other ports and because of .this the coating thus obtained has not been evenly .applied. Inorder tosecure a more desirable division of the material discharged -by the various ports .applicant has evolved the nozzle shown herein in which a-restrictionlis positioned in the nozzle after each set of ports. This tends to hold back the forward flow of atomized material sufii- .ciently to provide the ports with the proper amount of material. The balance of the atomizing .material proceeds to each successive series or set of ports which in-turn is provided with its .restriction designed toholdback sufficient mate- .rial. The final residue of material reaches the end ports andis discharged therefrom.

.By .having the forwardly inclined lateral ports .positioned rearwardly of the rearwardly inclined lateral ports, materialdischarged by these two sets of ports travel along converging paths and is deposited within a more confined area. This arrangement reduces the longitudinal movement necessary between the nozzle and shell and also enables the nozzle to be used on a shell cavity, the opposed surfaces of which are too close to coat otherwise. It is of course necessary, should the paths of the jetscross, that the jets of atomized material "do not meet .nor interfere with each other. The ports of one series are therefore staggered in relation to those of the other series and the jets of material from one series pass between the jets from the other set while traveling toward the surface.

While several specific embodiments of the invention are shown and described herein, it will .be understood that various changes in the size,

shape, position and number of orifices of such nozzles,.as well as in the shape of the interior of the nozzle without departing from the spirit of the invention.

Having thus described my invention what I claim as new and desire .to secure by Letters Patent is:

In. a spray nozzle utilizing air for atomizingand directing coating material upon surfaces facing in various-directions, the rear end of the nozzle being adapted to communicate with a sourceof supply for the air and materiaha mixing and dis- .charge chamber extending axially through the .-.nozzle from said end, an intermediate elongated cylindrical section of the chamber, an enlarged forward end of the chamber with a diameter greater than that of the cylindrical section, an

inwardly extending truncated annular ridge forminga restricted communicating passage between the cylindrical section-and the enlarged .forward end of the chamber, forwardly directed discharge port means in the enlarged forwardend of the chamber, and laterally directed discharge port means in the chamber immediately to the rear of the restricting ridge.

DONALD J. PEEPS.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS 

